Hello, Annex A I think is a standard of how ADSL is delivered. Elsewhere in Europe Annex B is used. So, for the UK we're interested in Annex A.
The numbers, are modem codes. So the firmware version and functionality is identical across the board, but the modem code steers how the ADSL port 'talks' to the line.
Other manufacturers give a "one size fits all" solution, usually, so you're probably used to only ever seeing one version of a firmware file.
The modem codes optimise performance.
So, for example on very long telephone lines where the equipment is miles away from the exchange, one of the modem codes will be best suited to this application, tweaked for snr / attenuation etc. and give best reliability, for example perhaps modem code 310811.
Or perhaps you're fairly close to the exchange, and you have an ADSL2+ service with Annex M enhanced double upstream - so there's a modem code for that too, possibly 3471101.
There isn't an exhaustive defined list in the public domian that I'm aware of. The general protocol is to contact draytek support by email (raise a ticket on the .co.uk site) with your stats, and they will advise by return the most suitable modem code version.
Hope this helps, regards, Neal
